OEM Carrier 40VA Transformer 120V–24V for Model PG8JAA048090ACJA

This OEM Carrier control transformer is the factory-specified replacement for the Carrier PG8JAA048090ACJA gas furnace. The transformer steps down 120V line voltage to 24V AC to power the entire low-voltage control circuit — including the thermostat, gas valve, ignition board, and relay coils. When this transformer fails, the result is immediate and total: a blank thermostat display, no call-for-heat response, and zero furnace activity. A failed transformer is often misdiagnosed as a thermostat or control board issue, making this the first component to test with a voltmeter before replacing more expensive parts.

• Specs: 40VA rating | 120V AC primary | 24V AC secondary | 60 Hz | Foot-mount configuration | Wire-lead connections with insulated female connectors | Inline 3A fuse protection
• OEM vs Generic: This is a factory-authorized OEM part (superseded to HT680054) built to exact Carrier specifications. Generic transformers frequently use undersized cores and substandard insulation, leading to early thermal failure — especially in high-cycling applications.
• Install difficulty: 2/5 — Shut off power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to confirm 24V output post-install). Label all low-voltage wire connections before disconnecting the old unit. The new transformer mounts in the same foot-mount position as the original.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Direct OEM replacement for Carrier model PG8JAA048090ACJA gas furnaces. OEM part number HT01BC116 has been superseded by HT680054 — both numbers are fulfilled by the same current-production factory part. Also replaces HT01BC115, HT01BC120, HT01BB126, and HT01CT120. Verify your existing transformer's voltage and VA rating on the data plate before ordering. Our fitment team is available to confirm compatibility before you buy.